Optimization of Temperature and Drying Time of Lemongrass and Lime Juice to Produce Antioxidant-Rich Instant Powder

Lemongrass has the primary compounds antioxidants of citronellal and geraniol. Lime contains antioxidants of alkaloids, phenols, saponins, tannins, steroids, and flavonoids. These ingredients can be made into functional drink powders that easy served by the foam mat drying method. The temperature and drying time influence the antioxidant content of the final product. The purpose of this study was to obtain the optimal drying temperature and time for drying lemongrass and lime to produce a high antioxidant of instant powder. This study used Response Surface Methodology (RSM). Factor 1 is the drying temperature (X1) with a lower limit of 60°C and an upper limit of 70°C, and the drying time (X2) with a lower limit of 5 hours and an upper limit of 9 hours. The responses were tested for antioxidant levels, water content, yield, and solubility. The results showed that the optimal drying temperature was 61.23°C and a drying time of 8.73 hours. Verification of optimal conditions obtained IC50 of 44.019 ppm, the water content of 8.57%, yield 27.86%, and solubility of 64.08% with a deviation of each response less than 2% or the model obtained is good. Optimal drying conditions have produced instant powder of lemongrass and lime with high levels of antioxidants.